Machinery utilising rotating applicator wicks for controlling plant growth in broad acre situations is described in International Patent Application No. PCT/AU85/00039 to STEVENS WEEDBUG PTY LTD. Such machines typically include a plurality of relatively large rotor assemblies mounted on a frame for towing behind a tractor with each rotor assembly being driven by a hydraulic motor housed within the rotor assembly. While such machines are very effective for controlling plant/weed growth in a broad acre situation or a roadside situation they are generally not suitable for use in many hard to get at places such as under fences, in gullies and on dams, other banks and rises, and commonly undesired weed or other plant growth in such places is still controlled by the use of motor driven hand guided brush cutters or in some cases even by brush hooks and the like.
It will be appreciated that growth of undesired weeds and grasses is not effectively controlled by brush cutters as the undesired plants in many cases can regenerate after cutting at a greater rate than the desirable plants so that regular treatment is necessary. On the other hand, selectively killing undesired plants by chemical treatment allows the desirable plants, particularly grasses, to cover the area of ground where the undesired plant previously existed thereby keeping undesired plants choked out.
Hand held implements for selective chemical treatment of undesired plants have been available for some time but such implements typically involve a user wiping the selected plant with a stationary wick which draws liquid chemical from a reservoir. However, such implements typically require the user to wipe the wick several times over the plant to effectively apply the chemical so that the plant dies. Furthermore, such implements require individual selection of the plant to be killed by the operator and are thus not well suited to control undesired plants interspersed widely with desired plants over an area. In other words, such implements are not particularly suitable for selectively controlling plants according to height. Attempts have also been made to utilise free-wheeling rotary applicators with rotation being caused by engagement of the applicator with trees or other fixed objects in a field and thus is akin to the user wiping the plant to be treated with a wick. It is an object of the present invention to provide a hand held motor driven applicator for applying liquids particularly weedicides selectively to undesired plants whereby chemical control of such plants in relatively small areas can be achieved. It is a further object of the present invention to provide a hand held motor driven applicator which is effective for use over an entire field, garden or crop whereby the operator can apply a chemical to all plants above a predetermined height. It is still a further object of the present invention to provide an applicator which reliably applies liquid to the plants selected for treatment. Other objects and advantages of the present invention will hereinafter become apparent.